Cycloaliphatic compounds as odour- and taste-modifying agents

ABSTRACT

Process for the preparation of cycloaliphatic compounds useful as perfuming and odour-modifying agents in the manufacture of perfumes and perfumed products, and as flavouring and taste-modifying agents in the aromatization of foodstuffs in general and imitation flavours for foodstuffs, beverages, animal feeds, pharmaceutical preparations and tobacco products.

This is a division of application Ser. No. 292,723, filed Sept. 27,1972, now abandoned.

SUMMARY OF THE INVENTION

The compounds to which the present invention relates belong to the classof tricyclic derivatives having the partial formula ##SPC1##

For simplicity in referring to the various compounds of the invention,their derivatives or precursors, the nomenclature used throughout thisspecification will define the nature of the symbols X and Z by anappropriate combination of letters. This system of nomenclature will beappended to the numbers designating the various formulae givenhereinafter.

The invention relates to new cycloaliphatic compounds having the formula##SPC2##

Wherein the symbol Z represents a radical of formula ##EQU1## and Xrepresents a divalent radical of formula ##EQU2## WHEREIN R represents ahydrogen atom or an alkyl radical comprising from 1 to 6 carbon atoms,and

R¹ represents a hydrogen atom or an acyl radical.

The above mentioned compounds possess interesting organolepticproperties and, moreover, may be used as intermediates for thepreparation of other compounds having useful fragrant and flavouringproperties.

It is a further object of the present invention to provide a process forthe preparation of the compounds of formula I, as defined above, whichprocess comprises

A. Treating isoprene with a compound of formula ##SPC3##

Wherein X has the same meaning as that indicated for formula I, to yielda compound of formula I wherein Z represents a radical of formula##EQU3## or

B. Epoxidizing the compounds of formula ##SPC4##

Wherein a methyl group is bound to a carbon atom in position 4 or 5, andthe symbol R represents a hydrogen atom or an alkyl radical comprisingfrom 1 to 6 carbon atoms, to yield a compound of formula ##SPC5##

Or

C. Catalytically hydrogenating a compound of formula ##SPC6##

To yield a compound of formula ##SPC7##

Or

D. Reducing a compound of formula I (bh) or I (ah), as indicated underletter C., to yield an alcohol of formula ##SPC8##

respectively; or

E. Esterifying an alcohol of formula I (bi) or I (ai), as indicatedunder letter D., to yield an ester of formula ##SPC9##

respectively; or

F. Epoxidizing a compound of formula ##SPC10##

to yield an epoxide of formula ##SPC11##

which upon subsequent treatment with an acidic or a basic agent affordsa ketone of formula ##SPC12##

BACKGROUND OF THE INVENTION

One of the main objects of the aromatization of foodstuffs for instanceis to restore the original quality and nature of the flavour, aroma andtaste of a given foodstuff material. Very often in fact the organolepticproperties of foodstuffs particularly diminish or are somehow modifiedin the course of the processes of freezing and storage, or during themodifications, such as cooking or baking, to which the foodstuffs aresubjected in order to yield an edible material.

In the past the aromatization was mainly achieved by using materials ofnatural origin. Nowadays, however, synthetic chemical compounds are usedat an ever increasing rate. Said compounds possess the advantage ofbeing available very often in unlimited quantities and at prices lowerthan those of the natural materials. Moreover, due to the fact that theflavouring character of a natural material is the result of the overalleffect determined by the combination and interaction of each of itsconstituents, the effects achieved by said natural material are veryoften not as well reproducible as those obtained by the use of the puresynthetic compounds.

In the field of perfumery the man in the art has to solve a similarproblem in attempting to reconstitute the olfactive notes of certainnatural essential oils or extracts. The perfumer's creativity however iscontinually boosted by the finding of new synthetic compounds, theorganoleptic properties of which will enable him to introduceunprecedented olfactive characters or nuances into new phantasy perfumecompositions.

As a consequence, the problem that the chemical industry has to solve isto satisfy the increasing demand of organoleptically interestingchemicals in order to better suit the specific needs of flavourists andperfumers.

PREFERRED EMBODIMENTS OF THE INVENTION

As mentioned above, according to the invention the compounds of formulaI wherein Z represents a radical of formula (b) are prepared by treatingisoprene with a compound of formula II. Preferably, the said reaction,which formally may be represented by an addition of the Diels-Aldertype, can be carried out in the presence of an inhibitor ofpolymerization, e.g. in the presence of hydroquinone, pyrogallol or amixture of these two compounds in different respective proportions.

Equally, the above reaction can be carried out by treating the reactantsin the presence of the chosen inhibitor under an atmosphere of an inertgas, such as e.g. nitrogen or argon. However, this specific operationtechnique does not bring about any substantial improvement of the totalyield of the thus obtained final product.

No particular addition agent is requested. The said addition is howeverbetter promoted by the action of heat and, in certain instances, of apressure higher than the atmospheric pressure. Thus it is preferred tooperate at a temperature comprised between about 100° and about 200° C,preferably between 150° and 180° C, and at a pressure comprised betweenabout 10 and 200 atmospheres. The temperature and pressure rangesindicated above may however vary within wide limits and values higher orlower than those indicated may be used.

The compounds of formula II, wherein X represents a radical of formula(e), (f) or (j), used as starting materials for the above mentionedprocess, are either materials commercially available, or compounds whichmay be prepared by known synthetic methods [see e.g.: Dutch Pat.application No. 66 13870].

The compounds of formula II, wherein X represents a radical of formula(g), (h), (i) or (i') may be obtained by the subsequent conversion ofthe corresponding compounds of formula II (e), II (f) or II (j)according to known chemical techniques, such as for instanceepoxidation, in order to form the corresponding epoxide derivatives;ring-opening of said epoxide derivatives, in order to form thecorresponding ketone derivatives; reduction of said ketone derivativesby means of metal hydrides, to form the corresponding alcohols; andesterification of said alcohols to form the corresponding esters.

In accordance with the process of the invention the compounds of formulaI (bg) are obtained by epoxidizing a compound of formula I (bf). Saidepoxidation can be carried out by means of an organic peracid such asperacetic, perbenzoic, monochloroperbenzoic, perphthalic, performic ortrifluoroacetic acid in an inert solvent such as e.g. a chlorinatedhydrocarbon, e.g. chloroform, methylene chloride, trichloroethylene ordichloroethane.

Moreover, the epoxidation can be carried out in a buffered medium.Typically, advantageous buffered media include an alkali metal salt ofan organic acid, such as e.g. formate, acetate, propionate, butyrate,oxalate, citrate or tartrate of sodium or potassium. Sodium acetate inmethylene chloride is preferred.

The temperature at which said epoxidation is carried out may vary withinwide limits. However, the best yields of the final products are obtainedby carrying out the epoxidation at a temperature of about 0° C or at alower one, preferably comprised between about 0° and -10° C. At highertemperatures a concomitant formation of a diepoxide of formula ##SPC13##

wherein a methyl group is bound to a carbon atom in position 4 or 5, andof a monoepoxide of formula ##SPC14##

takes place.

According to a specific embodiment of the process of the invention, theaforementioned epoxidation of the compounds of formula I (bf) can becarried out by means of a mixture comprising an organic nitrile andhydrogen peroxide at a pH of about 8.

Typically, the organic nitrile is benzonitrile and the reaction iscarried out in a solution able to keep the pH value at approximately 8.To this end an aqueous solution of sodium or potassiumhydrogenocarbonate is preferred [see e.g.: J. Org. Chem., 26, 659 (1961)and Tetrahedron, 18, 763 (1962)].

The organic peracids, used to promote the epoxidation of the exocyclicdouble bond of the compounds of formula I (bf), can be prepared in situby treating an organic acid, in the presence of small amounts of amineral acid, with hydrogen peroxide according to a technique known inthe art [see: H.O. House, Modern Synthetic Reactions, Benjamin, Inc.,New York (1965), p. 105 and ff.].

According to the process of the present invention the compounds offormula I (ah) are obtained by catalytically hydrogenating a compound offormula I (bh). The catalysts commonly used for reducing an ethylenicdouble bond may be conveniently employed to this and [see: H.O. House,cited reference, pp. 1-22].

In accordance with the process of the present invention the compounds offormula I (bi) and I (ai) are obtained by reducing the carbonyl functionof the compounds of formula I (bh) and I (ah), respectively. Thereducing agents commonly known to promote the conversion of ketonic oraldehydic derivatives to secondary or primary alcohols, respectively,may be advantageously used [cf.: H.O. House, cited reference, pp. 23 andff.]. Sodium boron hydride is preferred.

A further object of the process of the present invention is to preparethe esters of formula I (bi') and I (ai') by esterifying according tothe usual synthetic procedures the alcohols of formula I (bi) and I(ai), respectively. This esterification can be carried out by means ofcommon esterifying agents, such as e.g. acyl halides or anhydrides, inthe presence of an organic base, preferably a tertiary organic nitrogenbase [cf. e.g.: L.F. Fieser and M. Fieser, Organic Chemistry, ReinholdPubl. Corp., New York, (1956), p. 174].

The process of the present invention relates further to the preparationof a ketone of formula I (de), which compound is obtained by epoxidizinga compound of formula I (be) and successively treating the obtainedepoxide compounds with an acidic or basic agent.

The above preparation may be represented by the following scheme:##SPC15##

The reaction conditions under which the compounds of formula I (bf) areconverted to compounds I (bg) may be conveniently used for carrying outthe hereinabove mentioned preparation. The subsequent ring-opening ofthe epoxide intermediate can be carried out by means of an acidic orbasic agent. A suitable class of acidic agents includes a protic mineralor organic acid, or a Lewis acid, such as e.g. BF₃, SnCl₄, FeCl₃ orAlCl₃. Boron trifluoride in diethyl ether solution is preferred.

Specific examples of the compounds defined by the various formulaeindicated throughout this specification include the following newcompounds:

4-methyl-5-oxo-tricyclo[6.2.1.0²,7 ]undecane,

4-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene,

9-ethylidene-4-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene,

9-ethylidene-5-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene,

9-[9,12-epoxy-ethyl]-4-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene,

9-[9,12-epoxy-ethyl]-5-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene,

9-acetyl-4-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene,

9-acetyl-5-methyl-tricyclo[6.2.1.0²,7 ]undecane,

9-[1-hydroxy-ethyl]-4-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene,

9-[1-hydroxy-ethyl]-5-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene,

9-[1-acetoxy-ethyl]-4-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene,

9-[1-acetoxy-ethyl]-5-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene,

9-[1-formoxy-ethyl]-4-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene,

9-[1-formoxy-ethyl]-5-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene,

9-vinyl-4-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene,

9-vinyl-5-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene,

9-[12,13-epoxy-ethyl]-4-methyl-tricyclo[6.2.1.0²,7 ]-4,5-epoxyundecane,

9-[12,13-epoxy-ethyl]-5-methyl-tricyclo[6.2.1.0²,7 ]-4,5-epoxyundecane.

The compounds prepared in accordance with the process of the presentinvention occur in the form of various stereoisomers. For instance, dueto the presence of an alkyl and an epoxide group, and of two hydrogenatoms in position 2 and 7 of the molecule, the compounds of formula I(bg) may be more suitably represented by the following general formula##SPC16##

The various isomers may be separated from each other by the conventionaltechnique of purification, for example preparative vapour phasechromatography, fractional distillation, preferably by means of spinningband columns, or fractional cristallization. However, in considerationof the fact that the organoleptic properties of the various isomers donot differ from each other significantly, the mixtures of isomers can beused as directly obtained by the process of the invention.

The compounds of formula I possess interesting organoleptic propertiesand, accordingly, may be used as flavouring ingredients for modifying,enhancing or improving the organoleptic properties of foodstuffs, animalfeeds, beverages, pharmaceutical preparations and tobacco products, forthe preparation of artificial flavouring compositions, and for thepreparation of perfumes and perfumed products. The term "foodstuff" isused broadly and includes, for example, coffee, tea or chocolate. Thecompounds of formula I may be used as perfuming ingredients in dilutedor concentrated perfume compositions. Due to their stability,particularly in basic media, these compounds may be used for masking,modifying or improving the olfactive properties of materials such ase.g. soaps, cleaning products, detergents, house-hold materials andcosmetics.

The compounds of formula I are equally useful as ingredients for thepreparation of artificial essential oils, floral essential oils forexample.

In perfume compositions, the compounds of the invention may develop avariety of notes, particularly woody, green or fruity notes, dependingupon the nature of the composition.

Interesting effects can be obtained when the compounds of formula Iconstitute from 0.5 to 5 percent by weight of the total composition;but, depending upon the effect required, the proportion of the compoundsI may be increased to 10 percent by weight, or even more.

When the compounds of formula I are used as flavouring ingredients, theycan equally develop or enhance various flavouring notes, particularlyfruity and green notes. They can in particular develop a fruity taste,reminiscent of citrus fruits, specifically grapefruit. Theconcentrations of the compounds I used for flavouring purposes can varywidely.

Typically, interesting flavouring effects can be achieved with amountsranging from 5 to 10 ppm, based on the weight of the product flavoured.However, in order to achieve special effects, this amount can be raisedto about 100 ppm. When the compounds I are used in flavouringcompositions, in admixture with other flavouring agents, they maytypically comprise from 0.1 to 15 percent of the total weight of thecomposition; and, in many cases, amounts from 1 to 10 percent by weightwill give the best results.

In all cases, the ranges mentioned above may be varied, in order toachieve specific organoleptic effects.

In particular, the compounds of formula I include the9-[9,12-epoxy-ethyl]-4- and9-[9,12-epoxy-ethyl]-5-methyltricyclo[6.2.1.0²,7 ]undec-4-ene, and the5-methyl-4-oxo-tricyclo[6.2.1.0²,7 ]undecane. This letter particularlydevelops the floral character of the composition to which it isincorporated, and possesses moreover a reinforcing and fixing power.

On the other hand, the hereinabove mentioned epoxides possess a typicalwoody and fruity note reminiscent of grapefruit.

The invention is illustrated by the following Examples, in which alltemperatures are given in degrees centigrade.

EXAMPLE 1 9-Ethylidene-4-methyl- and9-ethylidene-5-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene

A mixture of ethylidene norbornene (1500 g; 12.5 M), isoprene (900 g;13.2 M), hydroquinone (1 g) and pyrogallol (1 g) was heated in astainless steel autoclave at 160°-170° during 15 hours at a pressure ofca. 20 atm.

The reaction mixture was then directly distilled by means of a Vigreuxcolumn. There were thus obtained 1175 g of the desired product; b.p.55°-60°/0.001 Torr; yield 50%.

On separation by preparative vapour phase chromatography the endo andexo pure isomers were obtained in a proportion of approximately 80 and20, respectively.

Nmr : 1.67 (6h, s); 1.3-2.4 (12H); 5.15 (1H, m); 5.4 (1H, m) δ ppm;

Ms : m⁺ = 188 (58); m/e: 173 (6); 159 (7.5); 145 (6); 132 (20.5); 119(14); 105 (26.5); 94 (60); 93 (100); 79 (43); 67 (21); 53 (8.5); 41(18).

The analytical data given above refer to the mixture as directlyobtained in accordance with the described process.

EXAMPLE 2 9-[9,12-Epoxy-ethyl]-4-methyl- and9-[9,12-Epoxy-ethyl]-5-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene

1128 g (6 M) of the product prepared in accordance with the methoddescribed in Example 1, were put into a 10 l flask equipped withmechanical stirrer, thermometer and a dropping funnel stoppered by meansof a clacium chloride tube, together with 485 g of sodium acetate and3000 ml or methylene chloride. The whole was kept under vigorousstirring at a temperature of ca. -5°, whereupon 1150 g (6 M) of a 40%aqueous peracetic acid solution and 15 g of sodium acetate were addedduring 4 hours. The addition rate was such as to keep the temperaturebelow 0°. Once the addition was finished, the reaction mixture was keptat room temperature during ca. 3 hours, then filtered. The clearfiltrate thus obtained was washed with water, then with a 10 % aqueoussolution of sodium carbonate and finally with two fractions of 1000 mlof water. The organic extracts separated and combined were thenevaporated under reduced pressure to yield a residue which upondistillation by means of a fractionating column of the Fischer typeyielded 735 g (yield 60 %) of the desired product. B.p. 75°-80°/0.001Torr.

Nmr : 1.2 (3h, m); 1.66 (3H, s); 1.3-2.3 (12H); 2.8 (1H, m); 5.4 (1H, m)δ ppm

Ir : 3035, 1665 and 870 cm.sup.⁻¹.

By the same distillation it was possible to obtain 210 g of a diepoxidederivative having b.p. 80°-95°/0.001 Torr to which the followingstructural formula was attributed: ##SPC17##

EXAMPLE 3 9-Acetyl-4-methyl- and 9-acetyl-5-methyl-tricyclo[6.2.1.0²,7]undec-4-ene

A mixture of 27.2 g (0.2 M) of 2-acetyl-bicyclo[2.2.1]hept-5-ene endo,13.6 g (0.2 M) of isoprene, 0.1 g of pyrogallol and 0.1 g ofhydroquinone were heated in a sealed tube at ca. 160° during 15 hours.There was thus obtained an inside pressure of 15 atm.

The reaction mixture was then directly distilled by means of a Vigreuxcolumn and yielded the desired product possessing the endo isomericstructure with a yield of 22 % (9.0 g); b.p. 82°-4°/0.001 Torr.

Ir : 3030, 1712 cm.sup.⁻¹

Nmr : 1.62 (3h, s); 2.03 (3H, d); 1.2-2.5 (12H); 2.75 (1H, m); 5.4(8/10H, d); 5.85 (2/10H, t) δ ppm

Sm : m⁺ = 204 (8.5); m/e: 186 (4); 171 (5); 157 (5); 146 (100); 131(41); 117 (10); 105 (29); 91 (29); 79 (19); 66 (41.5); 55 (12.5); 43(46.5).

By replacing the endo-2-acetyl-bicyclo[2.2.1]hept-5-ene by thecorresponding exo isomer, there is obtained the desired product with theexo structure with a yield of 30 % (12.2 g).

Ir : 3035 and 1710 cm.sup.⁻¹

Nmr : 1.65 (3h, s); 2.03 (3H, s); 1.2-2.7 (13H); 5.4 (1H, m) δ ppm

Ms : m⁺ = 204 (49); m/e: 186 (2.3); 171 (2.8); 161 (39); 146 (88); 133(44.5); 119 (24); 105 (41.5); 93 (52.5); 81 (62); 66 (74.5); 55 (17); 43(100).

The endo-2-acetyl-bicyclo[2.2.1]hept-5-ene used as starting material forthe preparation indicated above can be obtained as follows:

A solution of 132 g (2 M) of cyclopentadiene in 150 ml of anhydrousdiethyl ether was rapidly added to a solution previously cooled at ca.0° of methyl vinyl ketone (125 g; 1.78 M) in 150 ml of anhydrous diethylether kept under vigorous stirring. The reaction mixture was thengradually heated to room temperature, then to reflux. After 15 hours ofthis treatment the solution was evaporated and the obtained residuedistilled by means of a Vigreux column. A mixture of the endo and exoisomers of 2-acetyl-bicyclo[2.2.1]hept-5-ene, in a ratio of 75 : 25, wasthus obtained; b.p. 69°-72°/7 Torr.

The two isomers have been separated from each other by means of adistillation using a fractionating column of the Fischer type oroccasionally a spinning band column.

endo:

Ir : 3060 and 1705 cm.sup.⁻¹

Nmr : 1.2-1.8 (4h); 2.01 (3h, s); 2.8 (2H, m); 3.15 (1H, m); 5.72 (1H, dof d, J=5 cps, J¹ =3 cps); 5.97 (1H, d of d) δ ppm

Ms : m⁺ = 136 (9.5); m/e: 93 (12); 77 (8); 71 (16.5); 66 (100); 58 (8);43 (23) ##SPC18##

exo:

Ir : 3065 and 1710 cm.sup.⁻¹

Nmr : 1.2-2.5 (5h); 2.12 (3h, s); 2.9 (2H, m); 6.05 (2H, t, J=2 cps) δppm

Ms : m⁺ = 136 (14); m/e: 93 (13); 77 (12); 71 (26.5); 66 (100); 55 (5);43 (24).

EXAMPLE 4 9-Vinyl-4-methyl- and 9-vinyl-5-methyl-tricyclo[6.2.1.0²,7]undec-4-ene

A mixture of 120 g (1 M) of vinyl norbornene, 68 g of isoprene (1 M) and0.2 g of hydroquinone was heated in a sealed tube at ca. 165° during 15hours, whereupon an internal pressure of 15 atm. was reached.

The reaction mixture was then distilled by means of a Vigreux column toyield the desired product having b.p. 65°-70°/0.001 Torr; 65.5 g (yield35%).

Ir : 3095, 3035 and 1635 cm.sup.⁻¹

Nmr : 1.65 (3h, s); 1.2-2.8 (13H); 4.8 (2H, m); 5.4 (1H, m); 5.8 (1H, m)δ ppm

Ms : m⁺ = 188 (31); m/e: 173 (5.5); 159 (3); 146 (13); 134 (32); 119(26.5 ); 105 (28.5); 91 (39); 79 (38); 66 (100); 53 (8.5); 41 (21).

The product thus obtained was subjected to an epoxidation according tothe same procedure as that described for the preparation of9-[9,12-epoxy-ethyl]-4-methyl- and9-[9,12-epoxy-ethyl]-5-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene (cf.Example 2) by using the following ingredients in the givenquantities:9-vinyl-4-methyl- and 9-vinyl-5-methyl-tricyclo[6.2.1.0²,7]undec-4-ene 65 g (0.35 M)peracetic acid 40 % 71 g (0.37 M)anhydroussodium acetate 28.5 g (0.35)Mmethylene chloride 300 ml

On distillation by means of a Widmer column there were obtained 57.6 gof 9-vinyl-4-methyl- and 9-vinyl-5-methyltricyclo[6.2.1.0²,7]-4,5-epoxy-undecane, b.p. 67°-8°/0.001 Torr; and 10.0 g of9-[12,13-epoxy-ethyl]-4-methyl- and9-[12,13-epoxy-ethyl]-5-methyl-tricyclo[6.2.1.0²,7 ]-4,5-epoxy-undecane.b.p. 68°-87°/0.001 Torr.

Ir : 3090 and 1635 cm.sup.⁻¹

Nmr : 1.18 (3h, s); 1.3-2.3 (13H); 2.72 (1H, d); 4.8 (2H); 5.65 (1H,m) δppm

Ms : m⁺ = 204 (29); m/e: 189 (11.5); 175 (22.5); 162 (25); 148 (35); 131(25); 117 (29); 105 (35); 91 (69); 79 (75); 66 (54); 55 (29); 43 (100).

By using 2.2 equivalents of peracetic acid for 1 equivalent of startingmaterial there is obtained the diepoxide derivative (see Ex. 2) with ayield of 80%.

Nmr : 1.2 (3h, s); 1.3-2.1 (13H); 2.2-2.9 (4H, m) δ ppm

Ms : m⁺ = 220 (6); m/e: 205 (4); 189 (18); 148 (35); 131 (21); 91 (30);79 (57); 66 (34); 55 (29); 43 (100).

EXAMPLE 5 endo-9-[1-Acetoxy-ethyl]-4-methyl- andendo-9-[1-Acetoxy-ethyl]-5-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene a.9-[1-Hydroxy-ethyl]-4-methyl- and9-[1-hydroxy-ethyl]-5-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene

A solution of 0.7 g (0.018 M) of sodium boron hydride in 7 ml of waterwas added dropwise under vigorous stirring to a solution of 7.3 g (0.036M) of 9-acetyl-4-methyl- and 9-acetyl-5-methyl-tricyclo[6.2.1.0²,7]undec-4-ene, prepared according to the procedure described in Example3, in 50 ml of methanol. The reaction mixture was kept at a temperaturecomprised between about 30° and 40° during the whole addition, whereuponit was heated at reflux during 2 hours. The volatile portions were thenevaporated and the residue extracted twice with diethyl ether. Thecombined organic extracts were washed with a 36 % solution of NaOH, thenwith water until neutrality. After drying over MgSO₄ and evaporation theobtained residue was distilled. There were thus obtained 6.4 g (87 %) ofthe desired product having b.p. 100°-103°/0.001 Torr.

Ir : 3400 cm ⁻ ¹

Nmr : 1.12 (3h, d); 1.67 (3H, s); 1.4-2.5 (13H); 2.5-3.6 (1H); 3.9 (1H,s); 5.4 (2/3H); 5.9 (1/3H) δ ppm

Ms : m⁺ = 206 (12); m/e: 188 (5); 173 (4); 159 (7.5); 145 (11); 132(22.5); 117 (9.5); 105 (14); 91 (21); 79 (26); 66 (100); 55 (7.5); 41(14).

b. Acetylation of the product obtained according to a)

A mixture of 4.1 g (0.02 M) of the hydroxylic compound obtainedaccording to a), 4.1 g of acetic anhydride (0.04 M) and 4.1 g ofanhydrous pyridine was heated during 2 hours on a water bath, then itwas poured onto crushed ice and extracted twice with diethyl ether. Theether extracts were combined and washed with a 10 % aqueous solution ofHCl (4 times), then with an aqueous solution of sodium carbonate (twice)and finally with water until neutrality. After drying on MgSO₄ thevolatile portions were evaporated and the residue obtained was distilledthrough a Vigreux column. There were thus obtained 4.1 g of the desiredproduct (yield 83 %); b.p. 90°-94°/0.005 Torr.

Ir : 1730 cm⁻ ¹

Nmr : 1.1 (3h, d); 1.66 (3H, s); 1.95 (3H, s); 1.3-2.8 (13H); 4.7 (1H,s); 5.4 (2/3H); 5.9 (1/3H) δ ppm

Ms : m⁺ = 248 (8); m/e; 188 (25); 173 (7); 159 (8); 145 (23); 132 (33);121 (23); 105 (21); 93 (35); 79 (30); 66 (100); 55 (23); 43 (65).

The procedure indicated hereinabove can equally be applied to the exoisomer of 9-acetyl-4-methyl- and 9-acetyl-5-methyl-tricyclo[6.2.1.0²,7]undec-4-ene to yield the corresponding acetoxy derivative in the exoform.

exo:

Ir : 1735 cm⁻ ¹

Nmr : 1.1 (3h, m); 1.65 (3H, s); 1.95 (3H); 4.5 (1H); 5.35 (2/3H); 5.9(1/3H) δ ppm

Ms : m⁺ = 248 (12); m/e: 188 (20); 173 (4.5); 159 (6.5); 145 (8.5); 132(14.5); 121 (16); 105 (19); 94 (46.5); 79 (32); 66 (100); 55 (23); 43(70).

EXAMPLE 6 Exo- and endo-9-acetyl-4-methyl- and9-acetyl-5-methyl-tricyclo[6.2.1.0²,7 ]undecane

2.04 g (0.010 M) of endo-9-acetyl-4-methyl- and9-acetyl-5-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene in 20 ml of ethanolwere subjected to a hydrogenation in the presence of 50 mg of PtO₂.After absorption of the theoretical amount of hydrogen (30 minutes), thereaction mixture was filtered and the clear filtrate evaporated untilcomplete elimination of ethyl alcohol. The residue thus obtained waspurified by passing it through a column of SiO₂ (70 g) by using as aneluant a mixture (95 : 5) of hexane and ether. After evaporation of thevolatile portions the desired product, the endo isomer, was obtained bydistillation using a bulb distillation apparatus; b.p. 60°/0.001 Torr;405 mg (yield 20 %).

Ir : 1710 cm⁻ ¹

Nmr : 0.9 (3h, d); 2.05 (3H, s); 1.2-2.5 (15H); 2.75 (1H, m) δ ppm

Ms : m⁺ = 206 (0.1); m/e; 188 (0.2); 173 (0.4); 163 (6); 148 (100); 135(34); 119 (3.5); 106 (9); 93 (12); 81 (15); 67 (19); 55 (15); 43 (32).

By carrying out the hydrogenation according to the same procedure asgiven above on the exo isomer of 9-acetyl-5-methyl- and9-acetyl-4-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene there is obtained thecorresponding exo-undecane derivative with a yield of 24 %.

Exo-9-acetyl-4-methyl- and exo-9-acetyl-5-methyl-tricyclo [6.2.1.0²,7]undecane:

Ir : 1710 cm⁻ ¹

Nmr : 0.9 (3h); 2.06 (3h, s); 1.2-2.1 (15H); 2.35 (1H, m) δ ppm

Ms : m⁺ = 206 (0); m/e: 188 (0.2); 163 (72); 148 (100); 135 (29.5); 121(14); 107 (22.5); 95 (36.5); 81 (79); 67 (79); 55 (49); 43 (39).

EXAMPLE 7 9-[1-Formoxy-ethyl]-4-methyl- and9-[1-formoxy-ethyl]-5-methyltricyclo[6.2.1.0²,7 ]undec-4-ene

A mixture of the hydroxylic compound obtained in accordance with theprocedure described in paragraph a) of Example 5 (10.3 g; 0.05 M) and 23g of 98 % formic acid (0.5 M) was heated during 2 hours at 40°. Aftercooling the reaction mixture was extracted twice with diethyl ether. Thecombined organic extracts were washed three times with an aqueoussaturated solution of sodium bicarbonate (10 ml) and then with wateruntil neutrality. After drying over magnesium sulphate, the extractswere evaporated under reduced pressure to yield a residue which, byfractional distillation, gave a product having b.p. 70°-1°/0.001 Torr;8.6 g (yield 73.5 %).

On purification by means of preparative vapour phase chromatography(CARBOWAX 20 M, column; 2.5 m; 220°) there are obtained the two pureendo and exo isomers of the desired product:

A :

ir : 1720 and 1180 cm⁻ ¹

Nmr : 1.2 (3h, d); 1.65 (3H, s); 4.8 (1H, m); 5.2 (1H, s); 7.92 (1H, s)δ ppm

Ms : m⁺ = 234; m/e: 188 (50); 173 (24.5); 159 (26); 145 (20.5); 132(100); 117 (16); 105 (25); 95 (44.5); 79 (44.5); 67 (12); 55 (10.5); 41(16).

B :

ir : 1725 and 1185 cm⁻ ¹

Nmr : 1.15 (3h, d); 1.65 (3H, s); 4.7 (1H, m); 5.25 (1H, m) 7.95 (1H, s)δ ppm

Ms : m⁺ = 234; m/e: 188 (11.5); 173 (4); 159 (8); 145 (29); 132 (18.5);122 (16); 105 (9.5); 91 (19); 79 (23 ); 66 (100); 55 (7); 41 (7).

EXAMPLE 8 5-Methyl-4-oxo-tricyclo[6.2.1.0²,7 ]undecane

a. A mixture of 715 g (7.6 M) of norbornene, 550 g (8.1 M) of isopreneand 2 g of pyrogallol was heated in a stainless steel autoclave at ca.150° during 15 hours. An internal pressure of 20 atm. is thus reached.The reaction mixture was then distilled by means of a Vigreux column andyielded 467 g (yield 38 %) of 5-methyl-tricyclo[6.2.1.0²,7 ]undec-4-enehaving b.p. 90°/10 Torr.

Ms : m⁺ = 162 (66); m/e: 147 (19); 134 (33); 119 (19); 105 (23) 94 (57);79 (64); 66 (100); 53 (20); 41 (35); 27 (15).

Nmr (ccl₄) : 0.9-1.8 (10H); 1.67 (3H, s); 1.90 (4H, m); 5.42 (1H, d,J=6.7 cps) δ ppm.

b. 24.3 g (0.15 M) of the product prepared according to a), 31 g ofanhydrous sodium acetate and 150 ml of methylene chloride were pouredinto a flask equipped with mecanical stirrer, thermometer and a droppingfunnel stoppered with a calcium chloride tube. The whole was kept undervigorous stirring at ca. 0° , whereupon there is added during 15 minutesa 40 % solution of peracetic acid (29 g; 0.15 M) and 1 g of anhydroussodium acetate. The addition rate was such as to keep the temperaturecomprised between about 0° and 5°. Once the peracetic acid addition wasover, the reaction mixture was kept at room temperature during 3 hours,then filtered. The clear filtrate obtained was washed with water, thentwice with a 10 % aqueous solution of sodium carbonate (100 ml each) andfinally with water again. The organic layers were then evaporated underreduced pressure to yield a residue which on distillation through aVigreux column yielded 25.8 g of 5-methyl-4,5-epoxy-tricyclo[6.2.1.0²,7]undecane (yield 97 %), b.p. 110°/10 Torr.

Ms : m⁺ = 178 (35); m/e: 163 (30); 149 (40); 136 (21); 120 (9); 111(48); 92 (52); 79 (50); 67 (61); 55 (24); 43 (100); 27 (21)

Nmr (ccl₄) : 1.18 (3H, s); 2.73 (1H, d, J=3.9 cps) δ ppm.

C. 12.7 g (0.07 M) of the epoxide compound prepared in accordance withparagraph b) in 300 ml of dry toluene were poured into a flask equippedwith mecanical stirrer, thermometer and dropping funnel. To the reactionmixture kept at 20° there were then added during 30 minutes 19.8 g (0.14M) of trifluoroboroetherate, then 50 ml of a 5 % aqueous solution ofsodium bicarbonate. The solution which had acquired a brownish colourafter the addition of the trifluoroboroetherate became colourless. Itwas then washed with a 5 % aqueous solution of sodium bicarbonate (100ml) and with water (twice, 100 ml). The organic layer was dried overanhydrous magnesium sulphate and evaporated under reduced pressure. Byfractional distillation of the residue there are obtained 10.8 g of5-methyl-4-oxo-tricyclo[6.2.1.0²,7 ]undecane, b.p. 120°-2°/10 Torr(yield 85 %).

Ms : m⁺ = 178 (78); m/e: 163 (3); 150 (70); 136 (100); 121 (23); 109(43); 93 (39); 79 (66); 67 (91); 55 (37); 41 (64); 27 (27).

Nmr (ccl₄) : 1.08 (3H, d, J=7.5 cps) δ ppm

Ir (ccl₄) : 1710 cm⁻ ¹.

EXAMPLE 9 Perfume composition of the "Gardenia" type

A base perfume composition of the "Gardenia" type was prepared byadmixing the following ingredients (parts by weight):

    Phenylacetic aldehyde 10 % *                                                                            30                                                  Benzyl acetate            50                                                  Synth. jasmin             250                                                 Ylang                     60                                                  Lynalyl acetate           90                                                  Methyl anthranilate       30                                                  β-Methylnaphtyl ketone                                                                             30                                                  Phenylethyl alcohol       100                                                 Hydroxycitronellal        80                                                  Cinnamic alcohol          70                                                  Heliotropin               30                                                  Benzyl salicylate         70                                                  Methyl salicylate         10                                                  Musk ketone               30                                                  Diethyl phthalate         70                                                                            1000                                                 * in diethyl phthalate                                                   

By adding to 96 g of the above given base composition 4 g of9-[9,12-epoxy-ethyl]-4-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene there isobtained a perfume composition possessing a rounder character than thatof the base composition and having as well floral and green notes moremarked than that one.

When 9-[9,12-epoxy-ethyl]-4-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene wasreplaced by 9-[9,12-epoxy-ethyl]-5-methyltricyclo[6.2.1.0²,7]undec-4-ene or by a mixture containing the two positional isomers,analogous effects were observed.

EXAMPLE 10 Perfumed soap

A base perfume composition of the Gardenia type was prepared accordingto the same procedure as that indicated in Example 9. Said basecomposition was then added in the proportion of 1 % by weight, based onthe finished product, to a non-perfumed commercial soap paste ("control"material).

A "test" material was prepared by admixing in the proportion of 1 % byweight, based on the finished product, a perfume composition obtained byadding to the base composition (96 parts) 4 parts by weight of a mixtureconsisting of 9-[9,12-epoxy-ethyl7-4-methyl- and9-[9,12-epoxy-ethyl]-5-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene.

The perfumed soap pastes were treated according to the usual techniquesin order to obtain toilet soaps.

The "test" soap possessed a perfume having a rounder character than thatof the "control" soap and having as well more marked floral and greennotes than that one.

EXAMPLE 11 Flavouring composition

A base flavouring composition was prepared by admixing one part byweight of orange terpenes with 9 parts by weight of 95 % ethyl alcohol(control).

Two flavouring compositions were prepared separately by admixing thefollowing ingredients (parts by weight):Orange terpenes 1.00 1.0095 %Ethyl alcohol 8.60 8.80Compound A * 0.40 0.20 10.00 10.00 * Compound A =9-[9,12-epoxy-ethyl]-4-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene

These two compositions represent the test compositions.

The aromatization of a diluted acid syrup, prepared by dissolving 650 gof glucose and 10 g of a 50 % solution of citric acid in 1000 ml ofwater, is carried out by adding 3 g of the test and control compositionto 1000 ml of the syrup prepared as indicated above. The foodstuffs thusflavoured were subjected to the organoleptic evaluation by a panel ofexperts. The foodstuff flavoured by the control composition was judgedas having a slight orange taste, whereas the foodstuffs flavoured by thetwo test compositions were judged as having a more pronounced taste ofgrapefruit as well as a woody note.

When 9-[9,12-epoxy-ethyl]-4-methyl-tricyclo[6.2.1.0².7 ] undec-4-ene wasreplaced by 9-[9,12-epoxy-ethyl]-5-methyl-tricyclo[6.2.1.0²,7]undec-4-ene or by a mixture of the two positional isomers, analogouseffects were observed.

EXAMPLE 12

7 g of a 1 % alcoholic solution of a mixture of9-[9,12-epoxy-ethyl]-4-methyl- and9-[9,12-epoxy-ethyl]-5-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene (in 95 %ethyl alcohol) were sprayed onto a mixture of tobacco of "americanblend" type (100 g). The tobacco thus flavoured was used to manufacturetest cigarettes, the smoke of which was then subjected to organolepticevaluation by comparison with nonflavoured cigarettes (control). Thetobacco used to prepare the control cigarettes was preliminarily treatedwith 95 % ethyl alcohol. A panel of experts unanimously defined thetaste of the test cigarette as being woodier than that of the controlcigarette.

EXAMPLE 13 Perfume composition of the "Lavender" type

A base perfume composition of the "Lavender" type was prepared byadmixing the following ingredients (parts by weight):Coumarin 50Muskambrette 20Lavandin oil 100Lynalyl acetate 300Linalol 200Synth. bergamot150White thyme oil 10Sage oil 10Synth. geranium 30α-Ionone 10Allylionone 20Diethyl phthalate 100 1000

By adding to the above base composition (90 parts) 10 parts by weight of5-methyl-4-oxo-tricyclo[6.2.1.0²,7 ]undecane there is obtained a perfumecomposition having a lavender character more pronounced than that of thebase composition.

I claim:
 1. 4-Methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene.
 2. Compounds offormula ##SPC19##wherein a methyl group is bound to a carbon atom inposition 4 or 5, as indicated by the dotted lines, and the symbol Rrepresents a hydrogen atom or an alkyl radical comprising from 1 to 6carbon atoms.
 3. 9-Ethylidene-4-methyl-tricyclo[6.2.1.0²,7 ]undec-4-ene.4. 9-Ethylidene-5-methyl-tricyclo[6.2.1.9²,7 ]undec-4-ene.